I would like some help.
I am posting an image below, I need that kind of selection border effect
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Before PS CS5, you had the extract filter (which was EPIC), then they decided to update it and mix it with the selection tools and "REFINE EDGE" came out, which needs a bit more work but you get even better results.
It's something long enough for not putting it here, but thanks to youtube... you can find a brilliant tutorial here: https://www.youtube.com/watch?v=soJdXsFx8V8&feature=youtu.be#aid=P9n5_Rj5c9Q
EDIT: If you want just to achieve the stroke effect around the girl, open the image in Illustrator first, draw a path around the wanted object and then play with the Dashed Line options. After that just copy paste the path into Photoshop as "Smart Object" and place it wherever needed. Here's an image from Illustrator: